1. Field of the Invention
This invention relates to a differential transmission cable and a method of manufacturing the differential transmission cable.
2. Description of the Related Art
As a method of manufacturing a differential transmission cable, for example, there is a method configured such that a foamed insulating material is disposed directly above a dual core conductor by a collective extrusion for coating, particularly, such as a method described in JP-A-2001-035270. In the foam molding by a conventional single screw extruder such as that being used in the JP-A-2001-035270, the screw is composed of only metal and temperature control is mainly carried out in the cylinder part.